Power feeding unit and power feeding system

ABSTRACT

A power feeding unit includes: an electrode array including a plurality of power feeding electrodes arranged side by side; a power feeding section configured to supply power to a power receiving unit via the electrode array; and a setting section configured to set a power feeding condition for each of the power feeding electrodes.

BACKGROUND CROSS REFERENCE TO RELATED APPLICATIONS

The Application is a Continuation Application of application Ser. No.14/301,097, filed Jun. 10, 2014 and claims the benefit of JapanesePriority Patent Application JP 2013-136223 filed Jun. 28, 2013, theentire contents of which are incorporated herein by reference.

The present disclosure relates to a power feeding unit and a powerfeeding system configured to wirelessly supply power.

Recently, attention has been focused on a power feeding system (wirelesspower feeding system) configured to wirelessly supply power to consumerelectronics (CE) devices such as a mobile phone and a portable musicplayer. In such a power feeding system, for example, a mobile phone(power receiving unit) is placed on a power feeding tray (power feedingunit), thereby the mobile phone is charged. In other words, in thewireless power feeding system, power feeding is performed withoutconnecting a power feeding unit to a power receiving unit via a cable.

Examples of a method of performing such wireless power feeding include amagnetic field coupling method such as an electromagnetic inductionmethod, an electric field coupling method, an electromagnetic wavetransmission method, and the like. Among them, the electric fieldcoupling method has advantages such as a high degree of freedom oflayout of the power receiving unit in power feeding, small leakage of anelectromagnetic field, and low heat generation. For example, JapaneseUnexamined Patent Application Publication (Translation of PCTApplication) No. 2009-53209 discloses a power feeding unit of theelectric field coupling method.

SUMMARY

In general, electronic apparatuses are desired to be safely used by auser. The power feeding system is also expected to be highly safe.

It is desirable to provide a power feeding unit and a power feedingsystem capable of improving safety.

According to an embodiment of the present disclosure, there is provideda power feeding unit, including: an electrode array including aplurality of power feeding electrodes arranged side by side; a powerfeeding section configured to supply power to a power receiving unit viathe electrode array; and a setting section configured to set a powerfeeding condition for each of the power feeding electrodes.

According to an embodiment of the present disclosure, there is provideda power feeding system, including: a power feeding unit; and a powerreceiving unit, wherein the power feeding unit includes an electrodearray including a plurality of power feeding electrodes arranged side byside, a power feeding section configured to supply power to the powerreceiving unit via the electrode array, and a setting section configuredto set a power feeding condition for each of the electrodes.

In the power feeding unit and the power feeding system according to theabove-described embodiments of the present disclosure, power is suppliedto the power receiving unit via the electrode array. In this operation,a power supply condition is set for each of the power feeding electrodesarranged in parallel to the electrode array.

According to the power feeding unit and the power feeding system of theabove-described embodiments of the present disclosure, since a powersupply condition is set for each of the power feeding electrodes, safetyis improved.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the technology as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the specification, serve to explain the principles of thetechnology.

FIG. 1 is an explanatory diagram illustrating an exemplary configurationof a power feeding system according to a first embodiment of the presentdisclosure.

FIGS. 2A and 2B are a plan diagram and a sectional diagram,respectively, illustrating an exemplary configuration of a power feedingunit illustrated in FIG. 1.

FIGS. 3A and 3B are a plan diagram and a sectional diagram,respectively, illustrating an exemplary configuration of a mobilebattery illustrated in FIG. 1.

FIGS. 4A and 4B are explanatory diagrams for explaining one state of thepower feeding system illustrated in FIG. 1.

FIG. 5 is a block diagram illustrating an exemplary configuration of thepower feeding unit illustrated in FIG. 1.

FIG. 6 is a block diagram illustrating an exemplary configuration of themobile battery illustrated in FIG. 1.

FIG. 7 is a flowchart illustrating an exemplary operation of the powerfeeding system illustrated in FIG. 1.

FIG. 8 is an explanatory diagram for explaining an exemplary operationof the power feeding system illustrated in FIG. 1.

FIG. 9 is an explanatory diagram for explaining another state of thepower feeding system illustrated in FIG. 1.

FIG. 10 is an explanatory diagram for explaining another state of thepower feeding system illustrated in FIG. 1.

FIG. 11 is a block diagram illustrating an exemplary configuration of apower feeding unit according to a modification of the first embodiment.

FIG. 12 is an explanatory diagram illustrating an exemplaryconfiguration of a power feeding system according to a secondembodiment.

FIGS. 13A and 13B are a plan diagram and a sectional diagram,respectively, illustrating an exemplary configuration of a power feedingunit illustrated in FIG. 12.

FIG. 14 is a block diagram illustrating an exemplary configuration ofthe power feeding unit illustrated in FIG. 12.

FIG. 15 is an explanatory diagram for explaining an exemplary operationof the power feeding system illustrated in FIG. 12.

FIG. 16 is an explanatory diagram illustrating an exemplaryconfiguration of a power feeding system according to a third embodiment.

FIG. 17 is a block diagram illustrating an exemplary configuration of apower feeding unit illustrated in FIG. 16.

FIG. 18 is an explanatory diagram for explaining an exemplary operationof the power feeding system illustrated in FIG. 16.

FIG. 19 is an explanatory diagram illustrating an exemplaryconfiguration of a power feeding system according to a fourthembodiment.

FIG. 20 is a block diagram illustrating an exemplary configuration of apower feeding unit illustrated in FIG. 19.

FIG. 21 is an explanatory diagram for explaining an exemplary operationof the power feeding system illustrated in FIG. 19.

FIG. 22 is an explanatory diagram illustrating an exemplaryconfiguration of a power feeding system according to a fifth embodiment.

FIG. 23 is a block diagram illustrating an exemplary configuration of amobile battery illustrated in FIG. 22.

FIG. 24 is a block diagram illustrating an exemplary configuration ofthe power feeding unit illustrated in FIG. 22.

FIG. 25 is an explanatory diagram illustrating an exemplaryconfiguration of a power feeding system according to a sixth embodiment.

FIG. 26 is a block diagram illustrating an exemplary configuration of apower feeding unit illustrated in FIG. 25.

FIG. 27 is a flowchart illustrating an exemplary operation of the powerfeeding system illustrated in FIG. 25.

FIG. 28 is an explanatory diagram for explaining an exemplary operationof the power feeding system illustrated in FIG. 25.

FIG. 29 is a block diagram illustrating an exemplary configuration of apower feeding unit according to a modification of the six embodiment.

FIG. 30 is an explanatory diagram illustrating an exemplaryconfiguration of a power feeding system according to a seventhembodiment.

FIG. 31 is a block diagram illustrating an exemplary configuration of apower feeding unit illustrated in FIG. 30.

FIG. 32 is a block diagram illustrating an exemplary configuration of amobile battery illustrated in FIG. 30.

FIG. 33 is a flowchart illustrating an exemplary operation of the powerfeeding system illustrated in FIG. 30.

FIG. 34 is an explanatory diagram illustrating an application example ofan embodiment.

FIG. 35 is a plan diagram illustrating an exemplary configuration of apower feeding unit according to a modification.

DETAILED DESCRIPTION

Hereinafter, some embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings. It isto be noted that description is made in the following order.

1. First Embodiment

2. Second Embodiment

3. Third Embodiment

4. Fourth Embodiment

5. Fifth Embodiment

6. Sixth Embodiment

7. Seventh Embodiment

8. Application Examples

1. First Embodiment [Exemplary Configuration]

FIG. 1 illustrates an exemplary configuration of a power feeding systemaccording to a first embodiment. A power feeding system 1 is a powerfeeding system configured to wirelessly supply power. It is to be notedthat a power feeding unit according to an embodiment of the presentdisclosure is embodied by the first embodiment, and is thereforedescribed together.

The power feeding system 1 includes a power feeding unit 10 and a mobilebattery 20. The power feeding unit 10 is a tray-type unit. The mobilebattery 20 on the power feeding unit 10 is placed on the power feedingunit 10, thereby a battery 27 (described later) incorporated in themobile battery 20 is charged. A plurality of power feeding electrodes 11(described later) are disposed on a top (a side to be in contact withthe mobile battery 20) of the power feeding unit 10, and power receivingelectrodes 21A and 21B (described later) are disposed on a bottom (aside to be in contact with the power feeding unit 10) of the mobilebattery 20. The power feeding unit 10 uses such electrodes to supplypower to the mobile battery 20 through electric field coupling.

FIG. 2A illustrates a plan diagram of the power feeding unit 10. FIG. 2Billustrates a sectional configuration in a II-II arrow direction of thepower feeding unit 10 illustrated in FIG. 2A. Power feeding electrodearrays 12A and 12B and eight antennas 14 are disposed on the side, whichis to be in contact with the mobile battery 20, of the power feedingunit 10.

The power feeding electrode arrays 12A and 12B are each configured of aplurality of power feeding electrodes 11 arranged in parallel. The powerfeeding electrodes 11 are electrodes that supply power to the mobilebattery 20. In this exemplary case, the power feeding electrodes 11 arearranged in a checkerboard pattern in each of the power feedingelectrode arrays 12A and 12B. The power feeding electrodes 11 may bearranged in any of other patterns without being limited thereto in eachof the power feeding electrode arrays 12A and 12B. Each of the powerfeeding electrode arrays 12A and 12B is covered with an insulator 13.Consequently, the power feeding electrodes 11 are coupled by an electricfield with the power receiving electrodes 21A and 21B of the mobilebattery 20 through the insulator 13 and the like.

An antenna 14 is an antenna for wireless communication of a wirelesscommunication section 15 (described later) of the power feeding unit 10with an access point 100. In this exemplary case, four of the eightantennas 14 are disposed so as to enclose the power feeding electrodearray 12A, and the remaining four antennas 14 are disposed so as toenclose the power feeding electrode array 12B.

FIG. 3A illustrates a plan diagram of the mobile battery 20. FIG. 3Billustrates a sectional configuration in a arrow direction of the mobilebattery 20 illustrated in FIG. 3A. Two power receiving electrodes 21Aand 21B are disposed on a side, which is to be in contact with the powerfeeding unit 10, of the mobile battery 20. The power receivingelectrodes 21A and 21B are electrodes configured to receive power fromthe power feeding unit 10. The power receiving electrode 21A is disposedat a position corresponding to the power feeding electrode array 12A ofthe power feeding unit 10. The power receiving electrode 21B is disposedat a position corresponding to the power feeding electrode array 12B ofthe power feeding unit 10. Each of the power receiving electrodes 21Aand 21B is covered with an insulator 23. Consequently, the powerreceiving electrodes 21A and 21B are each coupled by an electric fieldwith the power feeding electrodes 11 of the power feeding unit 10through the insulator 23 and the like.

FIGS. 4A and 4B illustrate a case where the mobile battery 20 is placedon the power feeding unit 10, in which FIG. 4A illustrates a sectionalview, and FIG. 4B illustrates a relative positional relationship betweenthe power feeding electrode arrays 12A and 12B and the power receivingelectrodes 21A and 21B. As illustrated in FIGS. 4A and 4B, area of thepower receiving electrode 21A is smaller than area of the power feedingelectrode array 12A. Similarly, area of the power receiving electrode21B is smaller than area of the power feeding electrode array 12B.Specifically, power feeding electrodes 11 in a region RA correspondingto the power receiving electrode 21A among the power feeding electrodes11 in the power feeding electrode array 12A are opposed to the powerreceiving electrode 21A. Similarly, power feeding electrodes 11 in aregion RB corresponding to the power receiving electrode 21B among thepower feeding electrodes 11 in the power feeding electrode array 12B areopposed to the power receiving electrode 21B. Consequently, even if auser places the mobile battery 20 on the power feeding unit 10 in such amanner that each of the power receiving electrodes 21A and 21B isslightly displaced from the center of each of the power feedingelectrode arrays 12A and 12B, the power receiving electrodes 21A and 21Bare allowed to be easily opposed to the power feeding electrodes 11 inthe power feeding electrode arrays 12A and 12B, respectively. Thus, inthe power feeding system 1, since a user is not necessary to mindalignment between the power receiving electrodes 21A and 21B and thepower feeding electrode arrays 12A and 12B, user convenience isimproved.

In such a configuration, as illustrated in FIGS. 4A and 4B, when a userplaces the mobile battery 20 in such a manner that each of the powerreceiving electrodes 21A and 21B is slightly displaced from the centerof each of the power feeding electrode arrays 12A and 12B, part of thepower feeding electrodes 11 (a portion P1) in the power feedingelectrode array 12B are protruded from a disposed region of the mobilebattery 20 in this exemplary case. Hence, if the power feeding unit 10supplies power to the mobile battery 20 using all the power feedingelectrodes 11 in the power feeding electrode array 12B, and if a usertouches the portion P1 by mistake, the user may be struck byelectricity. During power feeding, therefore, the power feeding unit 10supplies power to the mobile battery 20 mainly using the power feedingelectrodes 11 opposed to the power receiving electrodes 21A and 21Bamong the power feeding electrodes 11 in the power feeding electrodearrays 12A and 12B. In other words, the power feeding unit 10 suppliespower to the mobile battery 20 without using the power feedingelectrodes 11 in the portion P1. Consequently, the power feeding system1 performs power feeding more safely.

FIG. 5 illustrates an exemplary configuration of the power feeding unit10. The power feeding unit 10 includes the power feeding electrodearrays 12A and 12B, the antennas 14, a selector 16, a wirelesscommunication section 15, a power feeding section 17, switch sections18A and 18B, and a control section 19.

The selector 16 sequentially selects one of the eight antennas 14 basedon a selector control signal SSEL, and connects the selected antenna 14to the wireless communication section 15.

The wireless communication section 15 performs wireless communicationwith the access point 100 using the antenna 14 selected by the selector16. Specifically, in this exemplary case, the wireless communicationsection 15 performs wireless communication with the access point 100having two antennas 100A and 100B via wireless local area network (LAN).The wireless communication section 15 then acquires field intensity RPat reception and a transfer function H at transmission. The fieldintensity RP indicates received power (a scalar value), for example,so-called received signal strength indication (RSSI). The transferfunction H is a transfer function (vector values) when anelectromagnetic wave W transmitted from each of the eight antennas 14 isreceived by each of the two antennas 100A and 100B of the access point100. Specifically, for example, the transfer function H is expressed bythe following formula.

$\begin{matrix}{\begin{pmatrix}{R\; 1} \\{R\; 2}\end{pmatrix} = {\begin{pmatrix}{h\; 11} & \ldots & {h\; 18} \\{h\; 21} & \ldots & {h\; 28}\end{pmatrix}\begin{pmatrix}{T\; 1} \\{T\; 2} \\\vdots \\{T\; 8}\end{pmatrix}}} & (1)\end{matrix}$

where h11 to h28 each represent a matrix component of the transferfunction H, T1 to T8 each represent a transmission signal when theelectromagnetic wave W is transmitted from each of the eight antennas14, and R1 and R2 each represent a received signal when the transmissionsignal is received by the two antennas 100A and 100B of the access point100. The wireless communication section 15 supplies the field intensityRP and the transfer function H to the control section 19.

Although the wireless communication section 15 performs wirelesscommunication with the access point 100 via wireless LAN in thisexemplary case, this is not limitative. Alternatively, for example,wireless communication may be performed with a base station of a mobilephone via Long Term Evolution (LTE), for example. Alternatively, forexample, wireless communication may be performed with another electronicapparatus via Bluetooth (registered trademark), for example.

The power feeding section 17 generates an AC power signal SP between twoends thereof. A first end of the power feeding section 17 is connectedto the switch section 18A, and a second end thereof is connected to theswitch section 18B. For example, voltage amplitude of the power signalSP may be 1000 [Vpp], and frequency thereof may be 50 [kHz].

The switch section 18A selects one or more power feeding electrodes 11to be used for power feeding among the power feeding electrodes 11 inthe power feeding electrode array 12A based on the switch control signalSSWA, and connects the selected power feeding electrodes 11 to the firstend of the power feeding section 17. The switch section 18B selects oneor more power feeding electrodes 11 to be used for power feeding amongthe power feeding electrodes 11 in the power feeding electrode array 12Bbased on the switch control signal SSWB, and connects the selected powerfeeding electrodes 11 to the second end of the power feeding section 17.

The control section 19 controls the selector 16 via the selector controlsignal SSEL to acquire the field intensity RP and the transfer functionH from the wireless communication section 15, and controls the switchsections 18A and 18B via the switch control signals SSWA and SSWB basedon the field intensity RP and the transfer function H. Specifically, asdescribed later, first, the control section 19 controls the selector 16via the selector control signal SSEL, and thus sequentially connects oneof the eight antennas 14 to the wireless communication section 15 toacquire the field intensity RP and the transfer function H from thewireless communication section 15. As described later, the fieldintensity RP and the transfer function H are each in accordance with arelative positional relationship between the power feeding unit 10 andthe mobile battery 20 on the power feeding unit 10. The control section19 determines the power feeding electrodes 11 to be used for powerfeeding among the power feeding electrodes 11 in the power feedingelectrode arrays 12A and 12B based on the field intensity RP and thetransfer function H, and controls the switch sections 18A and 18B viathe switch control signals SSWA and SSWB to connect the power feedingelectrodes 11 to be used for power feeding to the power feeding section17.

FIG. 6 illustrates an exemplary configuration of the mobile battery 20.The mobile battery 20 includes a power supply circuit 25 and the battery27 in addition to the power receiving electrodes 21A and 21B. The powersupply circuit 25 generates a voltage suitable for charge of the battery27 based on a voltage generated between the power receiving electrodes21A and 21B. The power supply circuit 25 includes a rectifier circuit26. The rectifier circuit 26 rectifies a voltage (an AC signal)generated between the power receiving electrodes 21A and 21B, and isconfigured of a diode, for example. The power supply circuit 25generates a voltage suitable for charge of the battery 27 based on therectified signal, and charges the battery 27. The battery 27 storespower supplied from the power supply circuit 25, and is configured of arechargeable battery (secondary battery) such as, for example, a lithiumion battery.

The power feeding electrode arrays 12A and 12B each correspond to aspecific but not limitative example of “electrode array” in oneembodiment of the disclosure. The control section 19 corresponds to aspecific but not limitative example of “setting section” in oneembodiment of the disclosure. The wireless communication section 15corresponds to a specific but not limitative example of “communicationsection” in one embodiment of the disclosure.

[Operation and Functions]

Operation and functions of the power feeding system 1 according to thefirst embodiment are now described.

(Summary of Overall Operation)

First, summary of overall operation of the power feeding system 1 isdescribed with reference to FIGS. 5 and 6. In the power feeding unit 10,the selector 16 sequentially selects one of the eight antennas 14 basedon the selector control signal SSEL, and connects the selected antenna14 to the wireless communication section 15. The wireless communicationsection 15 performs wireless communication with the access point 100using the selected antenna 14 to acquire the field intensity RP and thetransfer function H. The power feeding section 17 generates the AC powersignal SP between the two ends thereof. The switch section 18A selectsone or more power feeding electrodes 11 to be used for power feedingamong the power feeding electrodes 11 in the power feeding electrodearray 12A based on the switch control signal SSWA, and connects theselected power feeding electrodes 11 to the first end of the powerfeeding section 17. The switch section 18B selects one or more powerfeeding electrodes 11 to be used for power feeding among the powerfeeding electrodes 11 in the power feeding electrode array 12B based onthe switch control signal SSWB, and connects the selected power feedingelectrodes 11 to the second end of the power feeding section 17. Thecontrol section 19 controls the selector 16 via the selector controlsignal SSEL to acquire the field intensity RP and the transfer functionH from the wireless communication section 15, and controls the switchsections 18A and 18B via the switch control signals SSWA and SSWB basedon the field intensity RP and the transfer function H. Consequently, thepower feeding unit 10 supplies power to the mobile battery 20 using theselected power feeding electrodes 11 in each of the power feedingelectrode arrays 12A and 12B.

In the mobile battery 20, the power receiving electrodes 21A and 21Breceive power from the mobile battery 20. The power supply circuit 25generates a voltage suitable for charge of the battery 27 based on avoltage generated between the power receiving electrodes 21A and 21B.The battery 27 stores power supplied from the power supply circuit 25.

(Detailed Operation)

FIG. 7 is a flowchart illustrating an exemplary operation of the powerfeeding system 1. In the power feeding system 1, the wirelesscommunication section 15 of the power feeding unit 10 performs wirelesscommunication with the access point 100 using the antennas 14, andacquires the field intensity RP and the transfer function H. The controlsection 19 determines the power feeding electrodes 11 to be used forpower feeding among the power feeding electrodes 11 in the power feedingelectrode arrays 12A and 12B based on the field intensity RP and thetransfer function H. This is described in detail below.

First, the control section 19 controls the selector 16 via the selectorcontrol signal SSEL to connect one of the eight antennas 14 to thewireless communication section 15 (step S1).

Subsequently, the wireless communication section 15 performs wirelesscommunication with the access point 100 using the antenna 14 selected instep S1 (step S2).

Subsequently, the wireless communication section 15 acquires fieldintensity RP and transfer function H through wireless communication instep S2, and supplies the field intensity RP and the transfer function Hto the control section 19 (step S3).

Subsequently, the control section 19 checks whether or not communicationis performed using all the eight antennas 14 (step S4). Whencommunication is performed using all the antennas 14, the process isadvanced to step S5. When communication is not performed using all theantennas 14, the process is returned to step S1, and another antenna 14is selected. In this way, steps S1 to S4 are repeated untilcommunication is performed using all the antennas 14.

When the control section 19 determines that communication is performedusing all the eight antennas 14 in step S4, the control section 19determines the power feeding electrodes 11 to be used for power feedingbased on the field intensity RP and the transfer function H acquired insteps S1 to S4 (step S5). Specifically, since the field intensity RP andthe transfer function H are each varied depending on a relativepositional relationship between the power feeding unit 10 and the mobilebattery 20 on the power feeding unit 10, the control section 19 graspsthe positional relationship based on the field intensity RP and thetransfer function H, and determines the power feeding electrodes 11 tobe used for power feeding.

FIG. 8 illustrates operation of determining the power feeding electrodes11. Hereinafter, for convenience of description, among the four antennas14 disposed in the periphery of the power feeding electrode array 12A,an antenna disposed on an upper side of the power feeding electrodearray 12A is denoted as antenna 141, an antenna disposed on a left sideof the power feeding electrode array 12A is denoted as antenna 142, anantenna disposed on a lower side of the power feeding electrode array12A is denoted as antenna 143, and an antenna disposed on a right sideof the power feeding electrode array 12A is denoted as antenna 144.

In this exemplary case, the mobile battery 20 is disposed while beingslightly shifted in a lower left direction of FIG. 8 on the powerfeeding unit 10. Specifically, the region RA corresponding to the powerreceiving electrode 21A is located at the lower left in a region of thepower feeding electrode array 12A. Similarly, the region RBcorresponding to the power receiving electrode 21B is located at thelower left in a region of the power feeding electrode array 12B. In thisexemplary case, the wireless communication section 15 receives theelectromagnetic wave W coming from the upper left direction of FIG. 8using the antennas 141 to 144. In this case, the field intensity RP ofthe electromagnetic wave W received by the antennas 143 and 144 is lowerthan the field intensity RP of the electromagnetic wave W received bythe antennas 141 and 142, respectively, since part of theelectromagnetic wave W is interrupted by the mobile battery 20 placed onthe power feeding unit 10. Furthermore, since propagationcharacteristics of the electromagnetic wave are varied by suchinterruption of the electromagnetic wave, amplitude and a phase of eachmatrix component of the transfer function H are also varied depending ona placed position of the mobile battery 20.

The control section 19 determines a place, at which the power receivingelectrode 21A is disposed, within a region of the power feedingelectrode array 12A based on the field intensity RP and the transferfunction H. The control section 19 then determines power feedingelectrodes 11 in the region RA, in which the power receiving electrode21A is determined to be disposed, as the power feeding electrodes 11 tobe used for power feeding among the power feeding electrodes 11 in thepower feeding electrode array 12A. Similarly, the control section 19determines power feeding electrodes 11 in the region RB, in which thepower receiving electrode 21B is determined to be disposed, as the powerfeeding electrodes 11 to be used for power feeding among the powerfeeding electrodes 11 in the power feeding electrode array 12B.

Subsequently, the control section 19 determines whether or not the powerfeeding electrodes 11 to be used for power feeding are normallydetermined in step S5 (step S6). In other words, the control section 19determines whether or not the mobile battery 20 is placed on the powerfeeding unit 10.

For example, when the mobile battery 20 is not placed on the powerfeeding unit 10, the field intensity RP concerning any of the antennas141 to 144 are high, and an amplitude value of any of matrix componentsof the transfer function H is a high value. Such field intensity RP andtransfer function H each have a special pattern different from that ofeach of the field intensity RP and the transfer function H in the casewhere the mobile battery 20 is placed on the power feeding unit 10. Whenan object other than the mobile battery 20 is placed on the powerfeeding unit 10, field intensity RP and a transfer function H aredifferent from the field intensity RP and the transfer function H,respectively, in the case where the mobile battery 20 is placed on thepower feeding unit 10.

FIG. 9 illustrates a case where a conductor C1 exists on the powerfeeding electrode array 12B. FIG. 10 illustrates a case where a humanfinger exists on the power feeding electrode array 12B. In such a case,field intensity RP and a transfer function H each have a specialpattern. For example, field intensity RP concerning any of the antennas141 to 144 has a low value, and an amplitude value of any of the matrixcomponents of the transfer function H has a low value. Alternatively,field intensity RP and matrix components of a transfer function Hconcerning two opposed antennas among the antennas 141 to 144 aredifferent from field intensity RP and matrix components of a transferfunction H, respectively, concerning other two antennas.

When each of the field intensity RP and the transfer function H has sucha special pattern, the control section 19 determines that the powerfeeding electrodes 11 to be used for power feeding are not allowed to benormally determined.

When the control section 19 determines that the power feeding electrodes11 to be used for power feeding are not allowed to be normallydetermined in this way, the process is advanced to step S7, and stepsS21 to S26 are repeated after waiting for a predetermined time. When thecontrol section 19 determines that the power feeding electrodes 11 to beused for power feeding are normally determined, the process is advancedto step S8.

Subsequently, the control section 19 controls the switch section 18A viathe switch control signal SSWA to connect the power feeding electrodes11 to be used for power feeding among the power feeding electrodes 11 inthe power feeding electrode array 12A to the first end of the powerfeeding section 17, and controls the switch section 18B via the switchcontrol signal SSWB to connect the power feeding electrodes 11 to beused for power feeding among the power feeding electrodes 11 in thepower feeding electrode array 12B to the second end of the power feedingsection 17 (step S8).

The power feeding section 17 generates an AC power signal SP between thetwo ends thereof, and the power feeding unit 10 supplies power to themobile battery 20 (step S9).

This the end of this flow.

In this way, in the power feeding system 1, the power feeding electrodearrays 12A and 12B are larger than the power receiving electrodes 21Aand 21B, respectively. Consequently, even if a user places the mobilebattery 20 on the power feeding unit 10 in such a manner that each ofthe power receiving electrodes 21A and 21B is slightly displaced fromthe center of each of the power feeding electrode arrays 12A and 12B,the power receiving electrodes 21A and 21B are allowed to be easilyopposed to the power feeding electrodes 11 in the power feedingelectrode arrays 12A and 12B, respectively, and thus user convenience isimproved.

In the power feeding system 1, the wireless communication section 15performs wireless communication with the access point 100 using theantennas 14 to acquire the field intensity RP and the transfer functionH, and the control section 19 determines the power feeding electrodes 11to be used for power feeding based on the field intensity RP and thetransfer function H. Consequently, for example, as illustrated in FIG.4, even if the mobile battery 20 is placed such that each of the powerreceiving electrodes 21A and 21B is slightly displaced from the centerof each of the power feeding electrode arrays 12A and 12B, safety isimproved during power feeding. Specifically, in such a case, the controlsection 19 is allowed to control such that the power feeding electrodes11 opposed to the power receiving electrodes 21A and 21B are mainly usedfor power feeding among the power feeding electrodes 11 in the powerfeeding electrode arrays 12A and 12B, and the power feeding electrodes11 (near the portion P1 in FIG. 4) that are not opposed to the powerreceiving electrodes 21A and 21B are not used for power feeding.Consequently, in the power feeding system 1, even if a user touches theportion P1 by mistake, it is possible to reduce a possibility of anelectric shock of the user, and improve safety during power feeding.

In addition, in the power feeding system 1, the wireless communicationsection 15 performs wireless communication with the access point 100using wireless LAN to acquire the field intensity RP and the transferfunction H. Specifically, since existing standardized communicationtechnique is allowed to be used, it is possible to reduce developmentcost, and reduce component cost through using general-purpose products.

[Effects]

As described above, in the first embodiment, the power feeding electrodearray is larger than the power receiving electrode, and the powerfeeding electrodes to be used for power feeding are selected among thepower feeding electrodes in each power feeding electrode array; hence,it is possible to improve user convenience, and improve safety duringpower feeding.

In the first embodiment, the field intensity RP and the transferfunction H are acquired through wireless communication with the accesspoint 100 using wireless LAN; hence, it is possible to reducedevelopment cost and component cost.

[Modification 1-1]

Although the wireless communication section 15 performs wirelesscommunication with the access point 100 before power feeding, this isnot limitative. For example, wireless communication may be performedduring power feeding. Modification 1-1 is now described in detail.

FIG. 11 illustrates an exemplary configuration of a power feeding unit10B according to the Modification 1-1. The power feeding unit 10Bincludes a wireless communication section 15B and a power feedingsection 17B. Before power feeding, the wireless communication section15B performs operation similar to that of the wireless communicationsection 15 according to the first embodiment. The wireless communicationsection 15B also performs wireless communication with the access point100 using the antennas 14 during power feeding, and detects whether ornot a person exists around the power feeding unit 10B based on a stateof the wireless communication (for example, the field intensity RP andthe transfer function H), and generates a control signal CTLcorresponding to results of the detection. The power feeding section 17Bperforms operation similar to that of the power feeding section 17according to the first embodiment before power feeding, and performs orstops power feeding based on the control signal CTL during powerfeeding. According to such a configuration, if a person exists aroundthe power feeding unit 10B during power feeding, power feeding isallowed to be stopped; hence, it is possible to improve safety duringpower feeding.

In the case of the first embodiment, for example, when the power feedingsystem is used as a power feeding system in which a digital camera isused in place of the mobile battery 20, and a battery incorporated inthe digital camera is charged, the power feeding unit 10 may acquirephotograph data from the digital camera during power feeding, and maytransfer the photograph data to, for example, network attached storage(NAS) via the access point 100.

[Modification 1-2]

Although the first embodiment is configured such that the power feedingelectrodes 11 to be used for power feeding are selected among the powerfeeding electrodes 11 in the power feeding electrode arrays 12A and 12B,this is not limitative. Alternatively, for example, a power feedingcondition may be set for each of the power feeding electrodes 11 in thepower feeding electrode arrays 12A and 12B. Specifically, for example,it may be configured that, among the power feeding electrodes 11 in thepower feeding electrode arrays 12A and 12B, the power feeding electrodes11 opposed to the power receiving electrodes 21A and 21B supply largepower, while the power feeding electrodes 11 that are not opposed to thepower receiving electrodes 21A and 21B supply small power.

[Modification 1-3]

Although four antennas 14 are disposed so as to enclose the powerfeeding electrode array 12A and four antennas 14 are disposed so as toenclose the power feeding electrode array 12B in the first embodiment,this is not limitative. Alternatively, for example, three or less orfive or more antennas 14 may be disposed so as to enclose the powerfeeding electrode array 12A, and three or less or five or more antennas14 may be disposed so as to enclose the power feeding electrode array12B.

[Modification 1-4]

Although the access point 100 includes the two antennas 100A and 100B inthe first embodiment, this is not limitative. Alternatively, forexample, the access point 100 may include one antenna or three or moreantennas.

[Modification 1-5]

Although the control section 19 selects the power feeding electrodes 11to be used for power feeding among the power feeding electrodes 11 inthe power feeding electrode arrays 12A and 12B based on the fieldintensity RP and the transfer function H in the first embodiment, thisis not limitative. Alternatively, for example, the power feedingelectrodes 11 to be used for power feeding may be selected based on oneof the field intensity RP and the transfer function H.

[Modification 1-6]

Although the wireless communication section 15 acquires the fieldintensity RP at reception in the first embodiment, this is notlimitative. Alternatively, the wireless communication section 15 mayacquire a transfer function at reception. The transfer function atreception is similar to the transfer function H at transmission (Formula(1)), and corresponds to a transfer function when an electromagneticwave W transmitted from each of the two antennas 100A and 100B of theaccess point 100 is received by each of the eight antennas 14.

2. Second Embodiment

A power feeding system 2 according to a second embodiment is nowdescribed. The second embodiment is configured such that the wirelesscommunication section 15 performs wireless communication using the powerfeeding electrodes 11 as antennas. It is to be noted that substantiallythe same components as those of the power feeding system 1 according tothe first embodiment are designated by the same numerals, anddescription of them is appropriately omitted.

FIG. 12 illustrates an exemplary configuration of a power feeding system2 according to the second embodiment. The power feeding system 2includes a power feeding unit 30. In the power feeding unit 30, thewireless communication section 15 performs wireless communication withthe access point 100 using the power feeding electrodes 11 in the powerfeeding electrode arrays 12A and 12B. Specifically, although thewireless communication section 15 according to the first embodimentperforms wireless communication using the antennas 14, the wirelesscommunication section 15 according to the second embodiment performswireless communication using the power feeding electrodes 11 asantennas.

FIG. 13A illustrates a plan diagram of the power feeding unit 30, andFIG. 13B illustrates a sectional configuration of the power feeding unit30 illustrated in FIG. 13A along a XIII-XIII arrow direction. The powerfeeding unit 30 includes power feeding electrode arrays 12A and 12B. Inother words, the power feeding unit 30 has a configuration similar tothe configuration of the power feeding unit 10 according the firstembodiment except that the antennas 14 are omitted. The power feedingelectrodes 11 in the power feeding electrode arrays 12A and 12B supplypower to the mobile battery 20, and serve as antennas when the wirelesscommunication section 15 performs wireless communication before powerfeeding.

FIG. 14 illustrates an exemplary configuration of the power feeding unit30. The power feeding unit 30 includes a selector 36 and a controlsection 39.

The selector 36 sequentially selects one of a plurality of power feedingelectrodes 11 in the power feeding electrode arrays 12A and 12B based onthe selector control signal SSEL, and connects the selected powerfeeding electrode 11 to the wireless communication section 15. Thewireless communication section 15 performs wireless communication withthe access point 100 using, as an antenna, the power feeding electrode11 selected by the selector 36, thereby acquires field intensity RP anda transfer function H, and supplies the field intensity RP and thetransfer function H to the control section 39.

As with the control section 19 according to the first embodiment, thecontrol section 39 controls the selector 36 via the selector controlsignal SSEL to acquire the field intensity RP and the transfer functionH from the wireless communication section 15, and controls the switchsections 18A and 18B via the switch control signals SSWA and SSWB basedon the field intensity RP and the transfer function H.

FIG. 15 illustrates operation of determining the power feedingelectrodes 11. In this exemplary case, the region RA corresponding tothe power receiving electrode 21A is located at the lower left in aregion of the power feeding electrode array 12A. Similarly, the regionRB is located at the lower left in a region of the power feedingelectrode array 12B. In this case, field intensity RP of anelectromagnetic wave W received by a power feeding electrode 11 (forexample, a power feeding electrode 111) opposed to the power receivingelectrode 21A among the power feeding electrodes 11 in the power feedingelectrode array 12A is lower than field intensity RP of anelectromagnetic wave W received by a power feeding electrode 11 (forexample, a power feeding electrode 112) that is not opposed to the powerreceiving electrode 21A. In other words, since part of theelectromagnetic wave W transmitted from the access point 100 to thepower feeding electrode 111 is interrupted by the power receivingelectrode 21A, the field intensity RP of the power feeding electrode 111becomes lower. Furthermore, since propagation characteristics of theelectromagnetic wave are varied by such interruption of theelectromagnetic wave, amplitude and a phase of each matrix component ofthe transfer function H are also varied depending on a placed positionof the mobile battery 20.

The control section 39 determines a place, at which the power receivingelectrode 21A is disposed, within a region of the power feedingelectrode array 12A based on the field intensity RP and the transferfunction H. The control section 39 determines the power feedingelectrodes 11 in the region RA, in which the power receiving electrode21A is determined to be disposed, as power feeding electrodes 11 to beused for power feeding among the power feeding electrodes 11 in thepower feeding electrode array 12A.

In this way, in the power feeding unit 30, the wireless communicationsection 15 performs wireless communication using the power feedingelectrode 11 as an antenna. Consequently, the antennas 14 are allowed tobe omitted; hence, it is possible to reduce component cost and makeappearance to be simpler. Moreover, since the power feeding electrodes11 that perform power feeding are also used as antennas for wirelesscommunication, it is possible to highly accurately determine the powerfeeding electrodes 11 opposed to the power receiving electrodes 21A and21B, and therefore possible to perform power feeding control morefinely.

As described above, in the second embodiment, since the wirelesscommunication section performs wireless communication using the powerfeeding electrodes as antennas, it is possible to reduce component costand make appearance to be simpler.

In the second embodiment, since the power feeding electrodes thatperform power feeding are also used as antennas for wirelesscommunication, it is possible to highly accurately determine the powerfeeding electrodes opposed to the power receiving electrodes and performpower feeding control more finely.

Other effects are similar to those in the case of the first embodiment.

[Modification 2-1]

Any of the Modifications of the first embodiment may be appropriatelyapplied to the power feeding system 2 according to the secondembodiment.

3. Third Embodiment

A power feeding system 3 according to a third embodiment is nowdescribed. The third embodiment is configured such that a power feedingunit has two wireless communication sections that perform wirelesscommunication with each other using antennas 14 different from eachother. It is to be noted that substantially the same components as thoseof the power feeding system 1 according to the first embodiment aredesignated by the same numerals, and description of them isappropriately omitted.

FIG. 16 illustrates an exemplary configuration of a power feeding system3 according to the third embodiment. The power feeding system 3 includesa power feeding unit 40. In the power feeding unit 40, two wirelesscommunication sections 45A and 45B (described later) perform wirelesscommunication with each other using antennas 14 different from eachother. Specifically, although the wireless communication section 15according to the first embodiment performs wireless communication withthe access point 100, the wireless communication sections 45A and 45Baccording to the third embodiment perform wireless communication witheach other.

FIG. 17 illustrates an exemplary configuration of the power feeding unit40. The power feeding unit 40 includes a selector 46, the wirelesscommunication sections 45A and 45B, and a control section 49.

The selector 46 sequentially selects two antennas 14 of the eightantennas 14 based on the selector control signal SSEL, and connects afirst antenna 14 to the wireless communication section 45A whileconnecting a second antenna 14 to the wireless communication section45B.

The wireless communication sections 45A and 45B use the antennas 14different from each other selected by the selector 46 to performwireless communication with each other, thereby each acquire fieldintensity RP and a transfer function H. The wireless communicationsections 45A and 45B each supply the acquired field intensity RP andtransfer function H to the control section 49.

As with the control section 19 according to the first embodiment, thecontrol section 49 controls the selector 46 via the selector controlsignal SSEL to acquire the field intensity RP and the transfer functionH from each of the wireless communication sections 45A and 45B, andcontrols each of the switch sections 18A and 18B via the switch controlsignals SSWA and SSWB based on the field intensity RP and the transferfunction H.

FIG. 18 illustrates operation of determining the power feedingelectrodes 11. The wireless communication sections 45A and 45B performwireless communication with each other using antennas 14 different fromeach other among the eight antennas 14. Specifically, for example, thewireless communication section 45A connected to the antenna 141 and thewireless communication section 45B connected to the antenna 142 mayperform wireless communication with each other. For example, thewireless communication section 45A connected to the antenna 141 and thewireless communication section 45B connected to the antenna 144 mayperform wireless communication with each other. For example, thewireless communication section 45A connected to the antenna 141 and thewireless communication section 45B connected to one of the antennas 14disposed in the periphery of the power feeding electrode array 12B mayperform wireless communication with each other. In this way, thewireless communication sections 45A and 45B perform wirelesscommunication with each other using two antennas 14 in variouscombinations.

In the wireless communication between the wireless communicationsections 45A and 45B in such a case, the electromagnetic wave isinterrupted by the mobile battery 20 at a condition different fromothers. Consequently, the field intensity RP has a value different fromothers depending on combinations of the antennas 14 used for wirelesscommunication among the antennas 141 to 144. Similarly, amplitude and aphase of each matrix component of the transfer function H are alsovaried depending on a placed position of the mobile battery 20.

The control section 49 determines a place, at which the power receivingelectrode 21A is disposed, within a region of the power feedingelectrode array 12A based on the field intensity RP and the transferfunction H. The control section 49 determines power feeding electrodes11 in the region RA, in which the power receiving electrode 21A isdetermined to be disposed, as the power feeding electrodes 11 to be usedfor power feeding among the power feeding electrodes 11 in the powerfeeding electrode array 12A.

In this way, in the power feeding unit 40, the two wirelesscommunication sections 45A and 45B perform wireless communication witheach other. The power feeding unit 40 is therefore allowed to operateeven in a circumstance without the access point 100 unlike in the caseof the first embodiment, and therefore user convenience is improved.

As described above, in the third embodiment, since the two wirelesscommunication sections perform wireless communication with each other,user convenience is improved. Other effects are similar to those in thecase of the first embodiment.

[Modification 3-1]

Any of the Modifications of the first and second embodiments may beappropriately applied to the power feeding system 3 according to thethird embodiment.

4. Fourth Embodiment

A power feeding system 4 according to a fourth embodiment is nowdescribed. The fourth embodiment is configured such that a power feedingunit has two wireless communication sections that perform wirelesscommunication with each other using power feeding electrodes 11different from each other as antennas. It is to be noted thatsubstantially the same components as those of the power feeding system 3according to the third embodiment are designated by the same numerals,and description of them is appropriately omitted.

FIG. 19 illustrates an exemplary configuration of a power feeding system4 according to the fourth embodiment. The power feeding system 4includes a power feeding unit 50. In the power feeding unit 50, twowireless communication sections 45A and 45B perform wirelesscommunication with each other using power feeding electrodes 11different from each other. Specifically, although the wirelesscommunication sections 45A and 45B according to the third embodimentperform wireless communication with each other using the antennas 14,the wireless communication sections 45A and 45B according to the fourthembodiment perform wireless communication using the power feedingelectrodes 11 as antennas.

FIG. 20 illustrates an exemplary configuration of the power feeding unit50. The power feeding unit 50 includes a selector 56 and a controlsection 59.

The selector 56 sequentially selects two power feeding electrodes 11among a plurality of power feeding electrodes 11 in the power feedingelectrode arrays 12A and 12B based on the selector control signal SSEL,and connects a first power feeding electrode 11 to the wirelesscommunication section 45A while connecting a second power feedingelectrode 11 to the wireless communication section 45B. The wirelesscommunication sections 45A and 45B perform wireless communication witheach other using the respective different power feeding electrodes 11selected by the selector 56 as antennas, thereby each acquire fieldintensity RP and a transfer function H and supply the field intensity RPand the transfer function H to the control section 19.

As with the control section 49 according to the third embodiment, thecontrol section 59 controls the selector 56 via the selector controlsignal SSEL to acquire the field intensity RP and the transfer functionH from each of the wireless communication sections 45A and 45B, andcontrols each of the switch sections 18A and 18B via the switch controlsignals SSWA and SSWB based on the field intensity RP and the transferfunction H.

FIG. 21 illustrates operation of determining the power feedingelectrodes 11. The wireless communication sections 45A and 45B use thepower feeding electrodes 11 different from each other as antennas amongthe plurality of power feeding electrodes 11 in the power feedingelectrode arrays 12A and 12B to perform wireless communication with eachother. Specifically, for example, the wireless communication section 45Aconnected to a power feeding electrode 11 (for example, a power feedingelectrode 111) located under the mobile battery 20 and the wirelesscommunication section 45B connected to another power feeding electrode11 (for example, a power feeding electrode 113) located under the mobilebattery 20 may perform wireless communication with each other. Forexample, the wireless communication section 45A connected to a powerfeeding electrode 11 (for example, a power feeding electrode 112) thatis not located under the mobile battery 20 and the wirelesscommunication section 45B connected to a power feeding electrode 11 (forexample, the power feeding electrode 113) located under the mobilebattery 20 may perform wireless communication with each other. Forexample, the wireless communication section 45A connected to a powerfeeding electrode 11 (for example, a power feeding electrode 112) thatis not located under the mobile battery 20 and the wirelesscommunication section 45B connected to one of the power feedingelectrodes 11 in the power feeding electrode array 12B may performwireless communication with each other. In this way, the wirelesscommunication sections 45A and 45B perform wireless communication witheach other using, as antennas, two power feeding electrodes 11 in any ofvarious combinations.

In such operation, field intensity RP is lower in the case of wirelesscommunication using the power feeding electrodes 111 and 113 than in thecase of wireless communication using the power feeding electrodes 112and 113. Specifically, while the power feeding electrodes 111 and 113are located under the mobile battery 20, the power feeding electrode 112is not located under the mobile battery 20. Consequently, anelectromagnetic wave is more easily interrupted by the mobile battery 20and therefore field intensity RP is lower in wireless communicationusing the power feeding electrodes 111 and 113 than in wirelesscommunication using the power feeding electrodes 112 and 113. Similarly,a transfer function H concerning the wireless communication between thepower feeding electrodes 111 and 113 has a smaller amplitude componentthan a transfer function H concerning the wireless communication betweenthe power feeding electrodes 112 and 113.

The control section 59 determines a place, at which the power receivingelectrode 21A is disposed, within a region of the power feedingelectrode array 12A based on the field intensity RP and the transferfunction H. The control section 59 determines power feeding electrodes11 in the region RA, in which the power receiving electrode 21A isdetermined to be disposed, as the power feeding electrodes 11 to be usedfor power feeding among the power feeding electrodes 11 in the powerfeeding electrode array 12A.

In this way, in the power feeding unit 50, the two wirelesscommunication sections 45A and 45B perform wireless communication witheach other using the power feeding electrodes 11 different from eachother as antennas. Consequently, the antennas 14 used in the thirdembodiment are allowed to be omitted; hence, it is possible to reducecomponent cost and make appearance to be simpler. Moreover, since thepower feeding electrodes 11 that perform power feeding are also used asantennas for wireless communication, it is possible to highly accuratelydetermine the power feeding electrodes 11 opposed to the power receivingelectrodes 21A and 21B, and therefore possible to perform power feedingcontrol more finely.

As described above, in the fourth embodiment, the wireless communicationsection performs wireless communication using the power feedingelectrodes as antennas; hence, it is possible to reduce component costand make appearance to be simpler.

In the fourth embodiment, since the power feeding electrodes thatperform power feeding are also used as antennas for wirelesscommunication, it is possible to highly accurately determine the powerfeeding electrodes opposed to the power receiving electrodes and performpower feeding control more finely.

Other effects are similar to those in the case of the third embodiment.

[Modification 4-1]

Any of the Modifications of the first to third embodiments may beappropriately applied to the power feeding system 4 according to thefourth embodiment.

5. Fifth Embodiment

A power feeding system 5 according to a fifth embodiment is nowdescribed. The fifth embodiment is configured such that a wirelesscommunication section is provided on a mobile battery side, and thewireless communication section performs wireless communication with theaccess point 100 using power receiving electrodes as antennas. It is tobe noted that substantially the same components as those of the powerfeeding system 1 and the like according to the first embodiment and thelike are designated by the same numerals, and description of them isappropriately omitted.

FIG. 22 illustrates an exemplary configuration of a power feeding system5 according to the fifth embodiment. The power feeding system 5 includesa mobile battery 70 and a power feeding unit 60. The mobile battery 70has a wireless communication section 75 (described later) that performswireless communication with the access point 100 using the powerreceiving electrodes 21A and 21B as antennas. Specifically, although thewireless communication section 15 of the power feeding unit 10 performswireless communication with the access point 100 in the power feedingsystem 1 according to the first embodiment, the wireless communicationsection 75 of the mobile battery 70 performs wireless communication withthe access point 100 in the power feeding system 5 according to thefifth embodiment. The mobile battery 70 transmits field intensity RP anda transfer function H acquired by the wireless communication section 75to a power feeding unit 60 via a communication section 71 (describedlater).

FIG. 23 illustrates an exemplary configuration of the mobile battery 70.The mobile battery 70 includes a selector 76, a wireless communicationsection 75, a control section 79, and a communication section 71.

The selector 76 sequentially selects one of the power receivingelectrodes 21A and 21B based on a selector control signal SSEL2, andconnects the selected power receiving electrode to the wirelesscommunication section 75.

The wireless communication section 75 performs wireless communicationwith the access point 100 using, as an antenna, the power receivingelectrode selected by the selector 76 between the power receivingelectrodes 21A and 21B, and acquires field intensity RP and a transferfunction H. The wireless communication section 75 then supplies thefield intensity RP and the transfer function H to the control section79.

The control section 79 controls the selector 76 via the selector controlsignal SSEL to acquire the field intensity RP and the transfer functionH from the wireless communication section 75, and supplies the fieldintensity RP and the transfer function H to the communication section71.

The communication section 71 supplies the field intensity RP and thetransfer function H supplied from the control section 79 to acommunication section 61 (described later) of the power feeding unit 60.As a communication method, for example, wired or wireless communicationmay be used. In the case of using wired communication, for example,universal serial bus (USB) (registered trademark) may be used. In thecase of using wireless communication, for example, near fieldcommunication (NFC) such as FeliCa (registered trademark) andTransferJet (registered trademark) may be used. In the case of usingsuch wireless techniques, the power receiving electrodes 21A and 21B maybe used as antennas.

FIG. 24 illustrates an exemplary configuration of the power feeding unit60. The power feeding unit 60 includes a communication section 61 and acontrol section 69. The communication section 61 performs communicationwith the communication section 71 of the mobile battery 70 to receivethe field intensity RP and the transfer function H, and supplies thefield intensity RP and the transfer function H to the control section69. The control section 69 controls the switch sections 18A and 18B viathe switch control signals SSWA and SSWB based on the supplied fieldintensity RP and transfer function H.

As described above, in the fifth embodiment, the wireless communicationsection is provided on the mobile battery side, and the wirelesscommunication section performs wireless communication with the accesspoint using the power feeding electrodes as antennas. According to sucha configuration, it is also possible to obtain effects similar to thoseof the first embodiment and the like.

[Modification 5-1]

Any of the Modifications of the first to fourth embodiments may beappropriately applied to the power feeding system 5 according to thefifth embodiment.

6. Sixth Embodiment

A power feeding system 6 according to a sixth embodiment is nowdescribed. The sixth embodiment is configured such that a power feedingunit beforehand performs power feeding (pre-power feeding) to the mobilebattery 20 using power feeding electrodes 11 in the power feedingelectrode arrays 12A and 12B, and determines power feeding electrodes 11to be used for main power feeding based on a detection value detected byan antenna during the pre-power feeding. It is to be noted thatsubstantially the same components as those of the power feeding system 1and the like according to the first embodiment and the like aredesignated by the same numerals, and description of them isappropriately omitted.

FIG. 25 illustrates an exemplary configuration of a power feeding system6 according to the sixth embodiment. The power feeding system 6 includesa power feeding unit 80. The power feeding unit 80 sequentially selectsone of the power feeding electrodes 11 in the power feeding electrodearrays 12A and 12B to perform pre-power feeding before performing mainpower feeding to the mobile battery 20. During the pre-power feeding, inthe power feeding unit 80, an antenna 84 (described later) and adetection section 85 (described later) detect a harmonic component of aradiation electromagnetic field emitted from each power feedingelectrode 11, and determines power feeding electrodes 11 to be used formain power feeding based on the detection result DET.

FIG. 26 illustrates an exemplary configuration of the power feeding unit80. The power feeding unit 80 includes eight antennas 84, a selector 86,a detection section 85, and a control section 89.

Each antenna 84 is a sensor that detects the harmonic component of theradiation electromagnetic field emitted from each power feedingelectrode 11 while the power feeding unit 80 sequentially selects one ofthe power feeding electrodes 11 in the power feeding electrode arrays12A and 12B to perform the pre-power feeding to the mobile battery 20,and includes, for example, a magnetic field probe or a micro-loopantenna. In this exemplary case, four of the eight antennas 84 aredisposed so as to enclose the power feeding electrode array 12A, whilethe remaining four antennas 84 are disposed so as to enclose the powerfeeding electrode array 12B.

During the pre-power feeding, the selector 86 sequentially selects oneof the eight antennas 84 based on the selector control signal SSEL, andconnects the selected antenna 84 to the detection section 85.

During the pre-power feeding, the detection section 85 detects theharmonic component of the radiation electromagnetic field based on thedetection signal output from the antenna 84 selected by the selector 86.

The control section 89 controls the switch sections 18A and 18B via theswitch control signals SSWA and SSWB to sequentially connect one of thepower feeding electrodes 11 in the power feeding electrode array 12A toa first end of the power feeding section 17, and sequentially connectone of the power feeding electrodes 11 in the power feeding electrodearray 12B to a second end of the power feeding section 17, and thusperforms pre-power feeding to the mobile battery 20. During thisoperation, the control section 89 controls the selector 86 via theselector control signal SSEL to sequentially connect the eight antennas84 to the detection section 85, and acquires the detection result DET ofthe harmonic component of the radiation electromagnetic field from thedetection section 85. As described later, the harmonic component variesin accordance with a relative positional relationship between the powerfeeding unit 80 and the mobile battery 20 on the power feeding unit 80.The control section 89 determines power feeding electrodes 11 to be usedfor main power feeding among the power feeding electrodes 11 in thepower feeding electrode arrays 12A and 12B based on the detection resultDET.

The antenna 84 corresponds to a specific but not limitative example of“electromagnetic field sensor” in one embodiment of the disclosure.

FIG. 27 is a flowchart illustrating an exemplary operation of the powerfeeding system 6.

First, the control section 89 controls the switch sections 18A and 18Bvia the switch control signals SSWA and SSWB to connect one of the powerfeeding electrodes 11 in the power feeding electrode array 12A to thefirst end of the power feeding section 17, and connect one of the powerfeeding electrodes 11 in the power feeding electrode array 12B to asecond end of the power feeding section 17 (step S21).

Subsequently, the power feeding section 17 performs pre-power feeding tothe mobile battery 20 (step S22).

Subsequently, the detection section 85 detects the harmonic component ofthe radiation electromagnetic field (step S23). Specifically, thecontrol section 89 controls the selector 86 via the selector controlsignal SSEL to sequentially connect the detection section 85 to one ofthe eight antennas 84. The detection section 85 detects the harmoniccomponent of the radiation electromagnetic field based on the detectionsignal supplied from that antenna 84, and supplies the detection resultDET to the control section 89.

Subsequently, the control section 89 checks whether or not the pre-powerfeeding is performed using all the power feeding electrodes 11 in thepower feeding electrode arrays 12A and 12B (step S24). When thepre-power feeding is performed using all the power feeding electrodes11, the process is advanced to step S25. When the pre-power feeding isnot performed using all the power feeding electrodes 11, the process isreturned to step S21, and the control section 89 selects another powerfeeding electrode 11. In this way, steps S21 to S24 are repeated untilthe pre-power feeding is performed using all the power feedingelectrodes 11.

When the control section 89 confirms that the pre-power feeding isperformed using all the power feeding electrodes 11 in step S24, thecontrol section 89 determines power feeding electrodes 11 to be used formain power feeding based on the detection result DET of the harmoniccomponent of the radiation electromagnetic field acquired in steps S21to S24 (step S25). Specifically, since the harmonic component varies inaccordance with a relative positional relationship between the powerfeeding unit 80 and the mobile battery 20 on the power feeding unit 80as described below, the control section 89 grasps the positionalrelationship based on the detection result DET of the harmoniccomponent, and determines the power feeding electrodes 11 to be used formain power feeding.

FIG. 28 illustrates operation of determining the power feedingelectrodes 11. Hereinafter, for convenience of description, among thefour antennas 84 disposed in the periphery of the power feedingelectrode array 12A, an antenna disposed on an upper side of the powerfeeding electrode array 12A is denoted as antenna 841, an antennadisposed on a left side of the power feeding electrode array 12A isdenoted as antenna 842, an antenna disposed on a lower side of the powerfeeding electrode array 12A is denoted as antenna 843, and an antennadisposed on a right side of the power feeding electrode array 12A isdenoted as antenna 844. In this exemplary case, a region RAcorresponding to the power receiving electrode 21A is located at thelower left in a region of the power feeding electrode array 12A.Similarly, a region RB corresponding to the power receiving electrode21B is located at the lower left in a region of the power feedingelectrode array 12B. In this case, for example, when pre-power feedingis performed using a power feeding electrode 11 (for example, a powerfeeding electrode 115) opposed to the power receiving electrode 21Aamong the power feeding electrodes 11 in the power feeding electrodearray 12A, a harmonic component of a radiation electromagnetic fielddetected by the antenna 842 has a higher intensity than a harmoniccomponent of a radiation electromagnetic field detected by the antenna842 when pre-power feeding is performed using a power feeding electrode11 (for example, a power feeding electrode 116) that is not opposed tothe power receiving electrode 21A. This is because when pre-powerfeeding is performed using the power feeding electrode 11 (for example,the power feeding electrode 115) opposed to the power receivingelectrode 21A, a displacement current is generated between the powerfeeding electrodes 115 and the power receiving electrode 21A, and aharmonic component of the displacement current is emitted as anelectromagnetic wave to a distance.

The control section 89 determines a place, at which the power receivingelectrode 21A is disposed, within a region of the power feedingelectrode array 12A based on the detection result DET of the harmoniccomponent of the radiation electromagnetic field. The control section 89then determines power feeding electrodes 11 in the region RA, in whichthe power receiving electrode 21A is determined to be disposed, as thepower feeding electrodes 11 to be used for main power feeding among thepower feeding electrodes 11 in the power feeding electrode array 12A.

Subsequently, the control section 89 determines whether or not the powerfeeding electrodes 11 to be used for main power feeding are normallydetermined, as in step S6 in the first embodiment (step S26). When thecontrol section 89 determines that the power feeding electrodes 11 to beused for main power feeding are not allowed to be normally determined,the process is advanced to step S7, and steps S21 to S26 are repeatedagain after waiting for a predetermined time. When the control section89 determines that the power feeding electrodes 11 to be used for powerfeeding are normally determined, the control section 89 selects powerfeeding electrodes 11 (step S8), performs main power feeding to themobile battery 20 (step S9), and finishes the flow, as in the case ofthe first embodiment.

In this way, in the power feeding system 6, pre-power feeding isperformed every power feeding electrode 11 before main power feeding,and the power feeding electrodes 11 to be used for main power feedingare determined based on the harmonic component of the radiationelectromagnetic field formed during the pre-power feeding. Consequently,in the power feeding system 6, since the power feeding unit or themobile battery is not necessary to have a wireless communication sectionunlike in the case of each of the first to fifth embodiments, a simpleconfiguration is achieved.

Moreover, in the power feeding system 6, since the harmonic component (ahigh-frequency electromagnetic field) of the radiation electromagneticfield is used, the electromagnetic wave is emitted to a more distantpoint than in the case of using a fundamental wave component of theradiation electromagnetic field. It is therefore possible to improvedetection sensibility and increase a degree of freedom of layout of theantennas 81 to 84 and the like. Consequently, since the power feedingelectrodes 11 opposed to the power receiving electrodes 21A and 21B areallowed to be accurately determined, it is possible to perform powerfeeding control more finely.

Although the harmonic component of the radiation electromagnetic fieldis used in this exemplary case, this is not limitative. For example, inthe case where the antennas 81 to 84 are allowed to be disposed close tothe power feeding electrode arrays 12A and 12B, an electromagnetic fieldof a fundamental wave component may be detected in place of the harmoniccomponent.

As described above, in the sixth embodiment, since the power feedingelectrodes to be used for main power feeding are determined based on theharmonic component of the radiation electromagnetic field formed bypre-power feeding, a simple configuration is achieved.

In the sixth embodiment, since the harmonic component is used, it ispossible to improve detection sensibility and perform power feedingcontrol more finely.

Other effects are similar to those in the case of the first embodiment,etc.

[Modification 6-1]

Although the detection section 85 detects the harmonic component of theradiation electromagnetic field formed by pre-power feeding before mainpower feeding in the sixth embodiment, this is not limitative. Forexample, the harmonic component of the radiation electromagnetic fieldmay be detected during main power feeding. Modification 6-1 is nowdescribed in detail.

FIG. 29 illustrates an exemplary configuration of a power feeding unit80B according to the Modification 6-1. The power feeding unit 80Bincludes the detection section 85B, a frequency variable filter 81, anantiphase signal generation section 82, and a power feeding section 87.The detection section 85B operates in the same way as the detectionsection 85 according to the sixth embodiment before main power feeding,and supplies a detection signal supplied from each antenna 84 to thefrequency variable filter 81. The frequency variable filter 81 is abandpass filter that allows passing of a signal in a special frequencyrange in the detection signal supplied from the detection section 85B.For example, the frequency variable filter 81 may be set so as to allowpassing of the strongest harmonic component. The antiphase signalgeneration section 82 generates a signal having a phase opposite to aphase of an output signal of the frequency variable filter 81. The powerfeeding section 87 includes a signal addition section 83. The signaladdition section 83 adds an output signal of the antiphase signalgeneration section 82 to an AC power signal. The power feeding section87 outputs the added signal as a power signal SP.

Consequently, in the power feeding unit 80B, it is possible to suppressthe harmonic component of the radiation electromagnetic field duringmain power feeding. Hence, it is possible to reduce a possibility ofinfluence of the harmonic component of the radiation electromagneticfield on a human, and improve safety during power feeding.

[Modification 6-2]

Any of the Modifications of the first to fifth embodiments may beappropriately applied to the power feeding system 6 according to thesixth embodiment.

7. Seventh Embodiment

A power feeding system 7 according to a seventh embodiment is nowdescribed. The seventh embodiment is configured such that a powerfeeding unit performs pre-power feeding using each of the power feedingelectrodes 11 in the power feeding electrode arrays 12A and 12B, anddetermines power feeding electrodes 11 to be used for main power feedingbased on whether the pre-power feeding is possible or not. It is to benoted that substantially the same components as those of the powerfeeding system 1 and the like according to the first embodiment and thelike are designated by the same numerals, and description of them isappropriately omitted.

FIG. 30 illustrates an exemplary configuration of a power feeding system7 according to the seventh embodiment. The power feeding system 7includes a power feeding unit 90 and a mobile battery 120. The powerfeeding unit 90 sequentially selects one of the power feeding electrodes11 in the power feeding electrode arrays 12A and 12B to perform thepre-power feeding before performing the main power feeding to the mobilebattery 120. During this operation, in the power feeding unit 90, amodulation section 93 (described later) modulates the power signal SPwith an address code ADR for identifying the selected power feedingelectrode 11 to generate a modulated power signal SP2. In the mobilebattery 120, when power given by pre-power feeding is received, ademodulation section 123 (described later) demodulates the power signalSP to acquire an address code ADR, and the address code ADR is suppliedto the power feeding unit 90. The power feeding unit 90 determines powerfeeding electrodes 11 to be used for main power feeding based on theaddress code ADR.

FIG. 31 illustrates an exemplary configuration of the power feeding unit90. The power feeding unit 90 includes a power feeding section 97, acommunication section 91, and a control section 99.

The power feeding section 97 includes the modulation section 93. Duringpre-power feeding, based on the switch control signals SSWA and SSWB,the modulation section 93 modulates the power signal SP to generate themodulated power signal SP2 based on an address code ADR for a powerfeeding electrode 11 selected by the switch section 18A among the powerfeeding electrodes 11 in the power feeding electrode array 12A, and anaddress code ADR for a power feeding electrode 11 selected by the switchsection 18B among the power feeding electrodes 11 in the power feedingelectrode array 12B. The power feeding section 97 supplies the modulatedpower signal SP2 to the power feeding electrodes 11 via the switchsections 18A and 18B.

During pre-power feeding, the communication section 91 performscommunication with a communication section 121 (described later) of themobile battery 120 to receive the address code ADR, and supplies theaddress code ADR to the control section 99. As a communication method,for example, wired or wireless communication may be used as in the caseof the communication sections 61 and 71 according to the fifthembodiment.

The control section 99 controls the switch sections 18A and 18B via theswitch control signals SSWA and SSWB to sequentially connect one of thepower feeding electrodes 11 in the power feeding electrode array 12A toa first end of the power feeding section 17, and sequentially connectone of the power feeding electrodes 11 in the power feeding electrodearray 12B to a second end of the power feeding section 17, and thusperforms pre-power feeding to the mobile battery 20. During thisoperation, the control section 99 controls the modulation section 93 viathe switch control signals SSWA and SSWB to modulate an AC power signalwith an address code ADR for the power feeding electrode 11 selected bythe switch sections 18A and 18B. The control section 99 determines powerfeeding electrodes 11 to be used for main power feeding among the powerfeeding electrodes 11 in the power feeding electrode arrays 12A and 12Bbased on the address code ADR supplied from the communication section91.

FIG. 32 illustrates an exemplary configuration of the mobile battery120. The mobile battery 120 includes the demodulation section 123 andthe communication section 121.

During pre-power feeding, the demodulation section 123 performsdemodulation processing based on a voltage (an AC signal) generatedbetween the power receiving electrodes 21A and 21B to acquire theaddress code ADR. The demodulation section 123 supplies the address codeADR to the communication section 121.

The communication section 121 supplies the address code ADR suppliedfrom the demodulation section 123 to the communication section 91 of thepower feeding unit 90.

FIG. 33 is a flowchart illustrating an exemplary operation of the powerfeeding system 7.

First, the control section 99 controls the switch sections 18A and 18Bvia the switch control signals SSWA and SSWB to connect one of the powerfeeding electrodes 11 in the power feeding electrode array 12A to afirst end of the power feeding section 97, and connect one of the powerfeeding electrodes 11 in the power feeding electrode array 12B to asecond end of the power feeding section 97 (step S41).

Subsequently, the power feeding section 97 generates the modulated powersignal SP2 based on the switch control signals SSWA and SSWB, andperforms pre-power feeding to the mobile battery 120 using the modulatedpower signal SP2 (step S42).

Subsequently, the demodulation section 123 acquires the address code ADR(step S43). The communication section 121 of the mobile battery 120supplies the address code ADR to the control section 99 via thecommunication section 91 of the power feeding unit 90.

Subsequently, the control section 99 checks whether or not the pre-powerfeeding is performed using all the power feeding electrodes 11 in thepower feeding electrode arrays 12A and 12B (step S44). When thepre-power feeding is performed using all the power feeding electrodes11, the process is advanced to step S45. When the pre-power feeding isnot performed using all the power feeding electrodes 11, the process isreturned to step S41, and the control section 99 selects another powerfeeding electrode 11. In this way, steps S41 to S44 are repeated untilthe pre-power feeding is performed using all the power feedingelectrodes 11.

When the control section 99 confirms that the pre-power feeding isperformed using all the power feeding electrodes 11 in step S44, thecontrol section 99 determines power feeding electrodes 11 to be used formain power feeding based on the address code ADR acquired in steps S41to S44 (step S45). Specifically, for example, the control section 99 maydetermine a power feeding electrode 11, the address code ADR for whichhas been acquired, as the power feeding electrode 11 to be used for mainpower feeding.

Subsequently, the control section 99 determines whether or not the powerfeeding electrodes 11 to be used for main power feeding are normallydetermined in step S45 as with step S6 in the first embodiment (stepS46). When the control section 99 determines that the power feedingelectrodes 11 to be used for power feeding are not allowed to benormally determined, the process is advanced to step S7, and steps S41to S46 are repeated after waiting for a predetermined time. When thecontrol section 99 determines that the power feeding electrodes 11 to beused for power feeding are normally determined, the control section 99selects power feeding electrodes 11 (step S8), performs main powerfeeding to the mobile battery 120 (step S9), and finishes the flow, asin the case of the first embodiment.

In this way, in the power feeding system 7, pre-power feeding isperformed every power feeding electrodes 11 before actual power feeding,and the power feeding electrodes 11 to be used for main power feedingare determined based on whether the address code ADR is acquired or not,i.e., based on whether the pre-power feeding is possible or not.Consequently, in the power feeding system 7, since the power feedingunit or the mobile battery is not necessary to have a wirelesscommunication section unlike in the case of each of the first to fifthembodiments, a simple configuration is achieved.

As described above, in the seventh embodiment, since the power feedingelectrodes to be used for main power feeding are determined based onwhether the address code ADR is acquired or not, a simple configurationis achieved. Other effects are similar to those in the case of the firstembodiment, etc.

[Modification 7-1]

Any of the Modifications of the first to sixth embodiments may beappropriately applied to the power feeding system 7 according to theseventh embodiment.

Application Examples

Application examples of the power feeding system described in any of theembodiments and the Modifications are now described.

FIG. 34 illustrates an application example of the power feeding systemaccording to any of the embodiments and the Modifications. In thisapplication example, a tray-type power feeding unit and a mobile phone220 incorporating a battery are used to configure a power feedingsystem. The power feeding unit 210 and the mobile phone 220 are eachconfigured of the power feeding system according to any of theembodiments and the Modifications.

The power supply system according to any of the embodiments and theModifications is applicable to an electronic apparatus in any field. Inaddition to the mobile phone, examples of the electronic apparatus mayinclude a digital camera, a video camcorder, a portable video gameplayer, and a mobile storage. In other words, the power supply systemaccording to any of the embodiments and the Modifications is applicableto an electronic apparatus including a battery in any field.

Although the present technology has been described with reference to theexample embodiments, the Modifications, and the application examplesdirected to an electronic apparatus hereinbefore, the technology is notlimited thereto, and various modifications or alterations thereof may bemade.

For example, while the two power feeding electrode arrays 12A and 12Bare provided in the embodiments and the Modifications, this is notlimitative. Alternatively, for example, as illustrated in FIG. 35, onepower feeding electrode array 312 may be provided. In this case,according to a method similar to that in any of the embodiments and theModifications, for example, power feeding may also be performed to themobile battery 20 only using the power feeding electrodes 11 opposed tothe power receiving electrodes 21A and 21B of the mobile battery 20among the power feeding electrodes 11 in the power feeding electrodearray 312.

It is possible to achieve at least the following configurations from theabove-described example embodiments of the disclosure.

(1) A power feeding unit, including:

an electrode array including a plurality of power feeding electrodesarranged side by side;

a power feeding section configured to supply power to a power receivingunit via the electrode array; and

a setting section configured to set a power feeding condition for eachof the power feeding electrodes.

(2) The power feeding unit according to (1), wherein the setting sectionselects one or more power feeding electrodes to be used for powerfeeding among the plurality of power feeding electrodes.(3) The power feeding unit according to (1) or (2), wherein the settingsection sets power to be fed for each of the power feeding electrodes.(4) The power feeding unit according to any one of (1) to (3), furtherincluding:

a plurality of antennas; and

a communication section configured to sequentially select one of theplurality of antennas to perform communication with a wireless unit,

wherein the setting section sets the power feeding condition based on acommunication state between the wireless unit and the communicationsection.

(5) The power feeding unit according to any one of (1) to (3), furtherincluding a communication section configured to sequentially select oneof the plurality of power feeding electrodes to perform communicationwith a wireless unit using the selected power feeding electrode as anantenna,

wherein the setting section sets the power feeding condition based on acommunication state between the wireless unit and the communicationsection.

(6) The power feeding unit according to any one of (1) to (3), furtherincluding:

a plurality of antennas; and

a first communication section and a second communication section beingconfigured to sequentially select respective mutually-different antennasof the plurality of antennas to perform communication with each other,

wherein the setting section sets the power feeding condition based on acommunication state between the first communication section and thesecond communication section.

(7) The power feeding unit according to any one of (1) to (3), furtherincluding a first communication section and a second communicationsection being configured to sequentially select respectivemutually-different power feeding electrodes of the plurality of powerfeeding electrodes to perform communication with each other using theselected power feeding electrodes as antennas,

wherein the setting section sets the power feeding condition based on acommunication state between the first communication section and thesecond communication section.

(8) The power feeding unit according to any one of (4) to (7), whereinthe setting section acquires the communication state based on one orboth of field intensity and a transfer function.(9) The power feeding unit according to any one of (4) to (8), whereinwhile the power feeding section supplies power to the power receivingunit, the power feeding section continues or stops power supply to thepower receiving unit based on the communication state.(10) The power feeding unit according to any one of (1) to (3), furtherincluding a plurality of electromagnetic field sensors,

wherein the power feeding section performs pre-power feeding whilesequentially selected one of the plurality of power feeding electrodesbefore performing main power feeding, and

the setting section sets the power feeding condition based on detectionresults of the plurality of electromagnetic field sensors during thepre-power feeding.

(11) The power feeding unit according to (10), wherein the plurality ofelectromagnetic field sensors each detect a harmonic component of anelectromagnetic field.(12) The power feeding unit according to (11), wherein the power feedingsection performs negative feedback control to allow the detectedharmonic component to be decreased based on the harmonic componentduring performing the main power feeding.(13) The power feeding unit according to any one of (1) to (12), whereinthe power feeding section wirelessly supplies power to the powerreceiving unit through electric field coupling.(14) A power feeding system, including:

a power feeding unit; and

a power receiving unit,

wherein the power feeding unit includes

an electrode array including a plurality of power feeding electrodesarranged side by side,

a power feeding section configured to supply power to the powerreceiving unit via the electrode array, and

a setting section configured to set a power feeding condition for eachof the electrodes.

(15) The power feeding system according to (14), wherein the powerreceiving unit further includes:

a plurality of power receiving electrodes;

a first communication section configured to sequentially select one ofthe plurality of power receiving electrodes to perform communicationwith a wireless unit using the selected power receiving electrode as anantenna; and

a second communication section configured to transmit a communicationstate between the wireless unit and the first communication section tothe setting section of the power feeding unit,

wherein the setting section sets the power feeding condition based onthe communication state.

(16) The power feeding system according to (14), wherein the powerfeeding section performs pre-power feeding while sequentially selectingone of the plurality of power feeding electrodes before performing mainpower feeding, and notifying the power receiving unit of electrodeidentification information corresponding to the selected power feedingelectrode.(17) The power feeding system according to (16), wherein the powerfeeding section performs the pre-power feeding by supplying a powersignal to the power receiving unit, the power signal being modulatedbased on the electrode identification information.(18) The power feeding system according to (16) or (17), wherein thepower receiving unit includes:

an identification information acquisition section configured to acquirethe electrode identification information; and

a communication section configured to transmit the electrodeidentification information to the setting section of the power feedingunit,

wherein the setting section sets the power feeding condition based onthe electrode identification information.

(19) The power feeding system according to any one of (14) to (18),wherein

the power feeding unit includes a predetermined number of electrodearrays,

the power receiving unit includes the predetermined number of powerreceiving electrodes, and

area of each of the electrode arrays is larger than area of each of thepower receiving electrodes.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A power feeding unit comprising: a power feedingsection configured to generate power; a plurality of power feedingoutput circuits configured to wirelessly supply the power to a powerreceiving unit; a plurality of antennas; a first switching sectionelectrically connected to the plurality of power feeding outputcircuits; a second switching section electrically connected to one ormore of the plurality of antennas; and a control section configured tocontrol the first switching section to select one or more of theplurality of power feeding output circuits to receive the power from thepower feeding section based on a communication state, and control thesecond switching section to select one of the plurality of antennas. 2.The power feeding unit according to claim 1, wherein the control sectionis further configured to set an amount of the power to be fed to each ofthe one or more of the plurality of power feeding output circuits thatis selected.
 3. The power feeding unit according to claim 1, furthercomprising: a communication section configured to perform wirelesscommunication with an electronic apparatus by selecting one of theplurality of power feeding output circuits as an antenna, wherein thecommunication state is the communication state between the electronicapparatus and the communication section.
 4. The power feeding unitaccording to claim 1, further comprising: a first communication section;and a second communication section, wherein the first communicationsection and the second communication section are configured to performcommunication with each other by selecting respective mutually-differentantennas of the plurality of antennas, and wherein the control sectionis further configured to control the first switching section to selectthe one or more of the plurality of power feeding output circuits toreceive the power from the power feeding section based on a secondcommunication state between the first communication section and thesecond communication section.
 5. The power feeding unit according toclaim 1, further comprising: a first communication section; and a secondcommunication section, wherein the first communication section and thesecond communication section are configured to perform communicationwith each other by selecting respective mutually-different power feedingoutput circuits of the plurality of power feeding output circuits, andwherein the control section is further configured to control the firstswitching section to select the one or more of the plurality of powerfeeding output circuits to receive the power from the power feedingsection based on a second communication state between the firstcommunication section and the second communication section.
 6. The powerfeeding unit according to claim 1, wherein the control section isfurther configured to acquire the communication state based on one of afield intensity, a transfer function, or a combination of the fieldintensity and the transfer function.
 7. The power feeding unit accordingto claim 6, further comprising a first communication section configuredto output the one of the field intensity, the transfer function, or thecombination of the field intensity and the transfer function to thecontrol section.
 8. The power feeding unit according to claim 1, furthercomprising: a plurality of electromagnetic field sensors, wherein thecontrol section is further configured to perform pre-power feeding bycontrolling the first switching section to select the one of theplurality of power feeding output circuits to receive a pre-power signalfrom the power feeding section, the pre-power signal is the power duringthe pre-power feeding, and perform main power feeding by controlling thefirst switching section to select the one or more of the plurality ofpower feeding output circuits to receive a main power signal from thepower feeding section based on detection results of the plurality ofelectromagnetic field sensors during the pre-power feeding, the mainpower signal is the power during the main power feeding.
 9. The powerfeeding unit according to claim 8, wherein each of the plurality ofelectromagnetic field sensors is configured to detect a harmoniccomponent of an electromagnetic field.
 10. The power feeding unitaccording to claim 9, wherein the control section is further configuredto perform a negative feedback control to decrease the harmoniccomponent that is detected.
 11. The power feeding unit according toclaim 1, wherein the plurality of power feeding output circuits isfurther configured to wirelessly supply the power to the power receivingunit through electric field coupling.
 12. A power feeding systemcomprising: a power receiving unit; and a power feeding unit including apower feeding section configured to generate power; a plurality of powerfeeding output circuits configured to wirelessly supply the power to thepower receiving unit; a plurality of antennas; a first switching sectionelectrically connected to the plurality of power feeding outputcircuits; a second switching section electrically connected to one ormore of the plurality of antennas; and a control section configured tocontrol the first switching section to select one or more of theplurality of power feeding output circuits to receive the power from thepower feeding section based on a communication state, and control thesecond switching section to select one of the plurality of antennas. 13.The power feeding system according to claim 12, wherein the powerreceiving unit further includes a plurality of power receiving inputcircuits; a communication section configured to select one of theplurality of power receiving input circuits to perform wirelesscommunication with an electronic apparatus; and a second communicationsection configured to transmit a second communication state between theelectronic apparatus and the second communication section to the controlsection of the power feeding unit, wherein the control section isconfigured to control the first switching section to select the one ormore of the plurality of power feeding output circuits to receive thepower from the power feeding section based on the second communicationstate.
 14. The power feeding system according to claim 12, wherein thecontrol section is further configured to notify the power receiving unitof electrode identification information corresponding to the one of theplurality of power feeding output circuits that is selected.
 15. Thepower feeding system according to claim 14, wherein the power receivingunit further includes an identification information acquisition sectionconfigured to acquire the electrode identification information; and acommunication section configured to transmit the electrodeidentification information to the control section of the power feedingunit, and wherein the control section is configured to perform mainpower feeding by controlling the first switching section to select theone or more of the plurality of power feeding output circuits to receivethe power from the power feeding section based on the electrodeidentification information that is received from the power receivingunit.
 16. The power feeding system according to claim 12, wherein theplurality of power feeding output circuits is a first predeterminednumber, wherein the power receiving unit further includes a plurality ofpower receiving input circuits that is a second predetermined number,and wherein a first area of each of the first predetermined number ofpower feeding output circuits is larger than a second area of each ofthe second predetermined number of power receiving input circuits. 17.The power feeding system according to claim 12, wherein the controlsection is further configured to acquire the communication state basedon one of a field intensity, a transfer function, or a combination ofthe field intensity and the transfer function.
 18. The power feedingsystem according to claim 17, wherein the power feeding unit furtherincludes a first communication section that is configured to output theone of the field intensity, the transfer function, or the combination ofthe field intensity and the transfer function to the control section.19. The power feeding system according to claim 12, wherein the powerfeeding unit further includes a plurality of electromagnetic fieldsensors, wherein the control section is further configured to performpre-power feeding by controlling the first switching section to selectthe one of the plurality of power feeding output circuits to receive apre-power signal from the power feeding section, and perform main powerfeeding by controlling the first switching section to electricallyconnect the one or more of the plurality of power feeding outputcircuits to receive a main power signal from the power feeding sectionbased on detection results of the plurality of electromagnetic fieldsensors during the pre-power feeding.
 20. The power feeding unitaccording to claim 19, wherein each of the plurality of electromagneticfield sensors is configured to detect a harmonic component of anelectromagnetic field, and wherein the control section is furtherconfigured to perform a negative feedback control to decrease theharmonic component that is detected.